Biological-Control (1)

Biological Control of Insects

Biological Control: Definition and History

• Biological control refers to the use of natural enemies to mitigate damage caused by insect pest populations.

• Functions as a tactic/approach within an Insect Pest Management System (IPMS), presenting a viable alternative strategy for protecting agriculture and forestry.

• Key agents include parasitoids and predators, which can be mass-produced and released into affected areas.

Biological Control Agents

• Parasitoids: Organisms that develop in or on a host, ultimately killing it. They are specialized in host selection and include species such as Ichneumonid wasps and Braconid wasps.

• Predators: Consume multiple prey to achieve maturity and include various species across different insect orders.

• Entomopathogens: Bacteria and fungi that act as biological controls against pests.

Advantages and Disadvantages of Biological Control

Advantages:

• Cost-effective and sustainable long-term pest management.

• Non-toxic and selective, minimizing harm to non-target organisms.

• Low risk of resistance development by pests.

Disadvantages:

• Biological control is not always applicable for all pests.

• Control levels may not be sufficient for all situations.

• High initial research and knowledge costs; expert supervision required.

Introduction to Biological Control Approaches

• Biological control can manipulate natural enemies through introduction, augmentation, or conservation of existing beneficial organisms.

• Understanding the ecology of pathogen-pest interactions is crucial for enhancing management strategies.

Role of Biological Control in Plant Protection

• Essential knowledge of forest and agro-ecosystems to effectively implement plant protection through biological control.

  • Identification of target insect pests and damage assessment.

  • Interface of plant-environment-pest interactions as a foundation for using permissible biological control agents.

History of Biological Control

Beginnings

• Initiated in the late 19th century; for example, the introduction of the Vedalia beetle to control the cottony cushion scale in Central America.

• By 1986, over 1162 successful introductions worldwide were documented with varying success rates:

  • 25% successfully regulated target pests.

  • 69% achieved intermittent control.

  • 6% failed.

Historical Periods of Biological Control

1. Preliminary Efforts (200 A.D. - 1887): Lack of scientific approach with haphazard introductions.

2. Intermediate Period (1888 - 1955): Marked by the first successful introduction of a biological control agent in the Cottony Cushion Scale Project.

3. Modern Period (1956 - Present): Characterized by systematic planning and evaluation of the impact of natural enemies.

Detailed History of Biological Control

Preliminary Period (200 A.D. - 1887)

• The first recorded use of biological control by the Chinese using ants for pest management.

• Other historical accounts of early biological control practices include the use of insects and birds for pest control in the Middle Ages.

Intermediate Period (1888 - 1955)

• Significant advancements began with the cottony cushion scale project in California.

• Developments included various biological control projects worldwide and foundational concepts for future biological control studies.

Modern Period (1956 - Present)

• Introduction of economic injury level and economic thresholds by Vern Stern and others laid groundwork for informed pest management strategies.

• Increased collaboration and establishment of global organizations to promote biological control research.

Approaches to Enhancing Biological Control

Classical Biological Control

• Involves importing natural enemies from the pest's area of origin to control invasive species.

• Emphasizes thorough evaluation and monitoring of pest problems and natural enemy dynamics.

Augmentative Biological Control

• Adding natural enemies to areas with low populations or insufficient control mechanisms.

  • Inoculation: Releases small numbers to gradually boost population.

  • Inundation: Release of large numbers for immediate pest reduction.

Conservation of Indigenous Natural Enemies

• Focuses on preserving and enhancing the effectiveness of existing natural enemies through sustainable practices, including reduced pesticide use.

Biological Control Agents: Parasitoids and Predators

Parasitoids

• Defined as organisms that live in or on a single host and typically kill it.

  • Major Groups: Ichneumonid wasps, Braconid wasps, Chalcid wasps, and Tachinid flies.

  • Developmentally holometabolous (egg, larva, pupa, adult stages).

Predators

• Predation defined as one species consuming individuals of another species for energy.

• Encompasses a variety of insects, spiders, and mites; significant for agricultural pest management.

Mass Production and Utilization of Biological Control Agents

Mass Production Techniques

• Essential for effective pest management and to transition from natural to specific biological control methods.

• Focus on understanding the biology and rearing techniques for parasitoids and predators.

Advantages of Mass-Released Biological Control Agents

• No harmful residues and environmental friendliness.

• Integral component of Integrated Pest Management (IPM) strategies.

Successful Examples in India

• Control of lantana weed by Telonemia scrupulosa.

• Utilization of insect predators and parasitoids like Trichogramma spp. against various crop pests.

Rearing and Maintenance of Biological Control Agents

Effective Rearing Systems

• Include natural, factitious, and artificial designs, ensuring food sources are accessible and support agent life cycles efficiently.

• Challenges include avoiding pesticide cross-contamination and ensuring a stable food supply.

Quality Assurance in Production

• Maintain high standards of quality to ensure efficacy in pest control.

• Emphasize reproductive success and adaptability of production methods to different environments.